This is a great product - amazon link
threading vehicles that supports children's schema - trajectory, enclosure - in & out, connecting and helps to invite, move & expand on smaller, scaled car play to the fine motor, hand & eye coordinated activity of threading - KnUW, PSRN & CLL, CD, patterns, colour, order, position, number & quantity.
Extend the threading itself by presenting the activity with wheeled dumper trucks, lorries and pink wheeled boxes for children to transport their strung, lined up vehicle beads wherever wanted ..
Please add on with threading activities you've found children enjoy ..